I downloaded the Windows 7 RTM last week using my MSDN subscription. Great OS. Not going to get into a review right now – I’m sure you can find many of them.
First I loaded Firefox up in safe mode. This cleared up the problem. Then I found from a Windows 7 forum that apparently some add-ons (extensions) don’t sit quite right with Windows 7. This seems plausible, especially since I’m using the 64-bit edition. So I disabled all of my extensions and switched them back on – one by one.
Low and behold, luckily I went from bottom-to-top as the offending plug-in was … Skype Extension for Firefox. With this add-on enabled the browser grinds to a halt almost completely, eats all memory and stops JS from working almost entirely.
So if you get this problem, check for this extension, disable it and let me know the results in the comments. I can’t be the only one experiencing this, surely?